If you don't have a programmer, or a working Arduino, you are kinda out of luck.Programmers can be found inexpensively, such ashttp://www.nkcelectronics.com/pocket-avr-programmer.htmlA programmer is a handy tool to have, everyone hobbyist should have one. Or, keep a working Arduino around to run a programming sketch on to program other devices.I've managed to accumulate 4 or 5 programmers, and use this one exclusively at the moment because it reliably programs the larger memory devices such as ATMega1284P:http://www.mouser.com/ProductDetail/Atmel/ATAVRISP2/?qs=sGAEpiMZZMv256HIxPBQcA8%252bsNH3cLLR

The programmer connects to your PC at one end with a USB cable.It connects at the other end to your Arduino board's ICSP 2x3 male header pins via a ribbon cable. The pocket pirate I linked to includes a 10-pin to 6-pin ribbon cable.

to drive the SCK, MOSI, MISO, and Reset pins on the ICSO header.If you can connect to them, this method does work. I still have a Duemilanove set up pins added to make the connections above. It takes a bit to set up all the files.

If you have Win7 or 8, there may be some extra fooling around to do as well to allow unsigned drivers, etc. I saw yesterday that perhaps pressing F8 on bootup provides the option to turn that checking off.